Kaon semileptonic decay form factors from N_f = 2 non-perturbatively O(a)-improved Wilson fermions

TL;DR

This paper reports on lattice QCD calculations of kaon semileptonic decay form factors using improved Wilson fermions, aiming to refine the determination of the CKM matrix element |V_us| with reduced statistical errors.

Contribution

First lattice QCD results for kaon decay form factors using non-perturbatively improved Wilson fermions, enabling more precise CKM matrix element extraction.

Findings

Form factors calculated at multiple quark masses

Small statistical errors achieved through double ratio techniques

Results facilitate improved |V_us| determination

Abstract

We present first results from the QCDSF collaboration for the kaon semileptonic decay form factors at zero momentum transfer, using two flavours of non-perturbatively O(a)-improved Wilson quarks. A lattice determination of these form factors is of particular interest to improve the accuracy on the CKM matrix element |V_us|. Calculations are performed on lattices with lattice spacing of about 0.08 fm with different values of light and strange quark masses, which allows us to extrapolate to chiral limit. Employing double ratio techniques, we are able to get small statistical errors.